Light emitting device, backlight module and display panel

ABSTRACT

Embodiments of the application provide a light emitting device, a backlight module and a display panel. The light emitting device comprises: a substrate; a plurality of light emitters mounted on the substrate; and a light-transmissive resin on each of the light emitters, wherein the resin is in close contact with the light emitter and a part of the substrate, a surface of the light-transmissive resin away from the light emitter and the substrate forms an exit surface, the center of the light emitter and the center of the exit surface are located in a first optical axis, a region of the exit surface near the first optical axis is recessed toward the light emitter to form a concave surface, which is configured to totally reflect part of light emitted from the center of the light emitter and transmit part of light emitted from the edge of the light emitter.

TECHNICAL FIELD

The present application relates to the field of display technology, inparticular to a light emitting device, a backlight module and a displaypanel.

BACKGROUND

With the development of electronic technology and the consumers'increasing requirements for display screen size and image quality, LCDhas become the mainstream development trend in the industry. Wherein,the backlight module in the LCD usually comprises an edge-lit backlightmodule and a bottom lighting module. Compared with the edge-litbacklight module, the bottom lighting module can greatly improve thebrightness and color display of the panel.

The backlight module in the related art uses a light emitting diode(LED) as a light source of the backlight module. The backlight modulecomprises a substrate, LEDs and a diffusion plate. A layer oflight-transmissive resin is also potted on each LED to protect it. Sincethe LED is potted with light-transmissive resin, the divergence angle ofthe light emitted by the LED is small. Therefore, there may bealternating light and dark portions and uneven color on the displaypanel. Generally, the following two solutions can be adopted to dealwith the above problems. One is to reduce the distance between adjacentLEDs, which however will lead to the need of more LEDs and is notconducive to energy saving. The other one is to increase the distancebetween the substrate and the diffusion plate, that is, to increase thelight mixing distance (i.e., the optical distance) of light, whichhowever will further increase the thickness of the backlight module andis not conducive to the lightweight and thinness development of thedisplay panel.

SUMMARY

The embodiments of the present application aim to provide a lightemitting device, a backlight module and a display panel, which areconducive to increasing the divergence angle of light from lightemitters, thereby increasing the spacing between adjacent lightemitters, and further reducing the number of light emitters whileensuring the lightweight, thereby saving energy consumption.

In a first aspect, the present application provides a light emittingdevice, comprising: a substrate; a plurality of light emitters mountedon the substrate; and a light-transmissive resin on each light emitterof the light emitters, wherein the resin is in close contact with thelight emitter and a part of the substrate, and a surface of the resinaway from the light emitter and the substrate forms an exit surface,wherein a center of the light emitter and a center of the exit surfaceare located in a first optical axis, and a region of the exit surfacenear the first optical axis is recessed toward the light emitter to forma concave surface, which is configured to totally reflect part of lightemitted from the center of the light emitter and transmit part of lightemitted from an edge of the light emitter.

The light emitting device according to the embodiment of the presentapplication improves the scattering angle of light from the lightemitter by defining the shape of the light-transmissive resin on thelight emitter, which is conducive to increasing the spacing betweenadjacent light emitters. A plurality of light emitters are mounted onthe substrate, and have centers and edges when viewed from above in adirection perpendicular to the substrate. The light emitter can be invarious shapes. For example, the light emitter is a cylinder, and theprojection of the light emitter is circular when viewed from above; or,the light emitter is a rectangular, the projection of the light emitteris rectangular when viewed from above. A light-transmissive resin isadhered onto the substrate and the light emitter, an exit surface isformed on the surface of the resin away from the light emitter and thesubstrate, and a first optical axis is formed by connecting the centerof the exit surface and the center of the light emitter. A portion ofthe exit surface near the first optical axis is recessed toward thelight emitter to form a concave surface. Concave surfaces have severalfunctions: first, when the light emitted from the center of the lightemitter passes through the concave surface, part of the light is totallyreflected by the concave surface onto the substrate, then reflected fromthe substrate, and then refracted and transmitted through the exitsurface of the non-concave area, which is conducive to reducing thelight intensity of the area above the center of the light emitter andimproving the uniformity of the light, and further is conducive toexpanding the divergence angle of the light from the center of the lightemitter, thereby increasing the spacing between adjacent light emitters;second, part of the light emitted from the edge of the light emitter canalso be transmitted through the concave surface, which is conducive toenhancing the light intensity of the area above the center of the lightemitter, thereby improving the uniformity of the light and improving thedisplay effect. Therefore, the provision of a concave surface on theexit surface of the light-transmissive resin is advantageous to expandthe divergence angle of light from each light emitter, increase thespacing between adjacent light emitters, and further reduce the numberof light emitters while ensuring the lightweight and the thinness of thelight emitting device, thereby saving energy consumption.

The light emitting device according to the embodiment of the presentapplication may further have the following additional technicalfeatures.

In some embodiments of the present application, the first optical axisis perpendicular to the substrate, and a line connecting the center ofthe light emitter and any point in the exit surface forms a first anglewith the first optical axis; light having the first angle that isgreater than 0 degree and less than or equal to 40 degrees, among thelight emitted from the center of the light emitter, is totally reflectedby the concave surface.

In some embodiments of the present application, the first optical axisis perpendicular to the substrate, and a line connecting the edge of thelight emitter and any point in the exit surface forms a second anglewith the first optical axis; light having the second angle in a range of0 to 10 degrees, among the light emitted from the edge of the lightemitter, is transmitted through the concave surface.

In some embodiments of the present application, an orthographicprojection of the resin on the substrate is circular; the diameter ofthe orthographic projection is 8 mm to 10 mm.

In some embodiments of the present application, when the diameter of theorthographic projection is 8 mm, the height of the resin in a directionperpendicular to the substrate is 2 mm; when the diameter of theorthographic projection is 10 mm, the height of the resin in thedirection perpendicular to the substrate is 2.52 mm.

In some embodiments of the present application, phosphors orlight-transmissive particles are provided in the resin.

In a second aspect, the present application provides a backlight module,which comprises the light emitting device according to the first aspectand a diffusion plate arranged above the light emitting device.

The embodiments of the present application use the light emitting deviceaccording to the first aspect as a backlight source. Thelight-transmissive resin is provided on the light emitter in the lightemitting device, a concave surface is provided on the exit surface ofthe resin, which is advantageous to expand the divergence angle of lightfrom each light emitter, increase the spacing between adjacent lightemitters, thereby reducing the number of light emitters while ensuringthe lightweight and the thinness and thereby saving energy consumptionof the backlight module.

The backlight module according to the embodiment of the presentapplication may further have the following additional technicalfeatures:

In some embodiments of the present application, the distance between thediffusion plate and the substrate is 3 mm to 10 mm.

In some embodiments of the present application, the distance betweenadjacent light emitters is 20 mm or more.

In a third aspect, the present application provides a display panelcomprising the backlight module according to the second aspect.

The display panel in the embodiment of the present application comprisesthe backlight module according to the second aspect. The backlightmodule comprises the light emitting device according to the firstaspect. Wherein, a light-transmissive resin is provided on the lightemitter, a concave surface is provided on the exit surface of the resin,which is advantageous to expand the divergence angle of light from eachlight emitter, increase the spacing between adjacent light emitters,thereby reducing the number of light emitters while ensuring thelightweight and the thinness, and thereby saving energy consumption ofthe display panel.

It should be understood that any product or method for implementing thepresent application does not necessarily require all of the advantagesdescribed above.

BRIEF DESCRIPTION OF DRAWINGS

In order to more clearly describe the technical solution of theembodiments of the present application or the prior art, drawings neededin the embodiments or the prior art will be briefly described below.Obviously, the drawings described below are for only some embodiments ofthe present application, other embodiments can be obtained by one ofordinary skills in the art based on the drawings illustrated herein.

FIG. 1 is a backlight module in the related art;

FIG. 2 is a top view of the light-transmissive resin of FIG. 1 on asubstrate;

FIG. 3 is a structural diagram of a light emitting device according toan embodiment of the present application;

FIG. 4 is a schematic cross-sectional view taken along line D-D in FIG.3 ;

FIG. 5 a is a standardized waveform diagram of a backlight module in therelated art;

FIG. 5 b is a standardized waveform diagram in which the abscissa isenlarged in the block of FIG. 5 a;

FIG. 6 a is a standardized waveform diagram of one of the light emittingdevices in the embodiment of the present application for lightingexperiments;

FIG. 6 b is a standardized waveform diagram in which the abscissa isenlarged in the block of FIG. 6 a;

FIG. 7 is a structural diagram of a resin according to an embodiment ofthe present application;

FIG. 8 is a structural diagram illustrating the first angle and thesecond angle according to the embodiment of the present application;

FIG. 9 a is a standardized waveform diagram of another light emittingdevice according to the embodiment of the present application forlighting experiments;

FIG. 9 b is a standardized waveform diagram in which the abscissa isenlarged in the block of FIG. 9 a;

FIG. 10 is a structural diagram of a backlight module according to anembodiment of the present application.

The reference numbers are as follows:

-   -   100′—substrate;    -   110—LED;    -   120′—diffusion plate;    -   100—substrate;    -   120—diffusion plate;    -   111—light-transmissive resin;    -   H—diameter;    -   L—height;    -   P—light mixing distance;    -   10—light emitting device;    -   130—light emitter;    -   140—resin;    -   141—exit surface;    -   A—the center of the light emitter;    -   B—the center of the exit surface;    -   C—first optical axis;    -   142—concave surface;    -   143—orthographic projection.

DETAILED DESCRIPTION

The technical solution in the embodiments of the application will bedescribed clearly in detail below with reference to the drawings in theembodiments of the present application. Obviously, the embodimentsdescribed herein are only some instead of all of the embodiments of thepresent application. All other embodiments obtained by those skilled inthe art based on the embodiments in the present application fall withinthe protection scope of the present application.

With the development of electronic technology and the consumers'increasing requirements for display screen size and image quality, LCDhas become the mainstream development trend in the industry. Wherein,the backlight module in the LCD usually comprises an edge-lit backlightmodule and a bottom lighting module. Compared with the edge-litbacklight module, the bottom lighting module can greatly improve thebrightness and color display of the panel.

As shown in FIG. 1 and FIG. 2 , a backlight module in the related artuses a light emitting diode (LED) as a light source of the backlightmodule. The backlight module comprises a substrate 100′, LEDs 110, adiffusion plate 120′, etc., and a layer of light-transmissive resin 111is potted on each LED 110 to protect it. Since the LED 110 is pottedwith the light-transmissive resin 111, the light emitted from the LED110 is not diffused through lenses and other components, resulting in asmall light divergence angle. Therefore, in order to improve thecondition of alternating light and dark portions and uneven color on thedisplay panel, the spacing between adjacent LEDs 110 can be set small.That is, more LEDs 110 need to be used, which is not conducive to savingenergy consumption; or, the distance between the substrate 100′ and thediffusion plate 120′, that is, the light mixing distance P of the light,i.e., the optical distance, can also be increased, which also can dealwith the above problems. However, this will increase the thickness ofthe backlight module and is not conducive to the development of thelightweight display panel.

To solve the above problems, the first aspect of the present applicationproposes a light emitting device 10, as shown in FIG. 3 and FIG. 4 .FIG. 4 is a cross-sectional view taken along the line D-D in FIG. 3 .The light emitting device 10 comprises a substrate 100, a plurality oflight emitters 130 mounted on the substrate 100, and alight-transmissive resin 140 on each light emitter of the light emitters130. The resin 140 is in close contact with the light emitter 130 and apart of the substrate 100. A surface of the resin 140 away from thelight emitter 130 and the substrate 100 forms an exit surface 141. Thecenter A of the light emitter 130 and the center B of the exit surface141 are located in the first optical axis C. A region of the exitsurface 141 near the first optical axis C is recessed toward the lightemitter 130 to form a concave surface 142, which is configured tototally reflect part of the light emitted from the center A of the lightemitter 130 and transmit part of the light emitted from the edge of thelight emitter 130.

The substrate 100 is a plate that carries the light emitter 130 and maybe a PCB or the like. The plurality of light emitters 130 are mounted onthe substrate 100. As shown in FIG. 3 , each light emitter 130 has acenter A and an edge when viewed from above in a direction perpendicularto the substrate 100. The light emitter 130 can be in various shapes.For example, the light emitter 130 is a cylinder, and the projection ofthe light emitter 130 is circular when viewed from above; or, the lightemitter 130 is a rectangular, and the projection of the light emitter130 is rectangular when viewed from above. The light emitter 130 may bean LED, a mining LED, or the like, which is not limited in the presentapplication. Preferably, the light emitter 130 may be an LED emittinglight from its upper surface.

A light-transmissive resin 140 is adhered to the light emitter 130, andthe resin 140 may be formed of silicone, acrylic resin, polycarbonate,methyl methacrylate or styrene copolymer, or the mixture of one or twoof them. The surface of the resin 140 away from the light emitter 130and the substrate 100 is an exit surface 141, and the center B of theexit surface 141 and the center A of the light emitter 130 are connectedto form a first optical axis C. A portion of the exit surface 141 nearthe first optical axis C is further recessed toward the light emitter130 to form a concave surface 142.

As shown in FIG. 4 , the concave surface 142 has several functions:first, when part of the light emitted from the center A of the lightemitter 130 passes through the concave surface 142, the light isreflected by the concave surface 142 to the substrate 100, thenreflected by the substrate 100, and then refracted and transmittedthrough the exit surface 141, so that it is conducive to reducing thelight intensity of the area above the center A of the light emitter 130and improving the uniformity of the light, while it is also conducive toexpanding the divergence angle of the light from the center of the lightemitter 130, thereby increasing the spacing between adjacent lightemitters 130; second, part of the light emitted from the edge of thelight emitter 130 can also be transmitted through the concave surface142, which is conducive to enhancing the light intensity of the areaabove the center A of the light emitter 130, thereby improving theuniformity of the light and improving the display effect.

Generally, a width at half height can be used to measure the spectralline width of a luminous object, and can also be used to measure thedispersion of light intensity. The width at half height refers to thespectral width when the light intensity drops to half of the maximumlight intensity. FIG. 5 a and FIG. 5 b show standardized waveformdistribution diagrams after an experiment using the backlight module inthe related art shown in FIG. 1 , wherein the light mixing distance Pfrom the substrate 100′ to the diffusion plate 120′ is 5 mm. As can beseen from FIG. 5 a and FIG. 5 b , the width at half height is about 16.5mm. FIG. 6 a , FIG. 6 b and FIG. 10 show standardized waveformdistribution diagrams of the light emitting device 10 according to theembodiment of the present application after performing a lightingexperiment on the diffusion plate 120, wherein the light mixing distanceP from the substrate 100 to the diffusion plate 120 is 5 mm. As can beseen from FIG. 6 a and FIG. 6 b , the width at half height is about 31mm, which is about 2 times larger than the width at half height of thebacklight module in the related art, so that a wider spacing arrangementbetween adjacent light emitters 130 can be realized, which is conduciveto reducing the number of light emitters 130. That is, the lightemitting device 10 according to the embodiment of the presentapplication can improve the light distribution of the light emitter 130and make the light from the light emitter 130 more discrete. Therefore,the provision of a concave surface 142 on the exit surface 141 of theresin 140 is advantageous to expand the divergence angle of light fromeach light emitter 130, increase the spacing between adjacent lightemitters 130, and further reduce the number of light emitters 130 whileensuring the lightweight and the thinness of the light emitting device10, thereby saving energy consumption.

In some embodiments of the present application, the orthographicprojection 143 of the resin 140 on the substrate 100 is circular; thediameter H of the orthographic projection 143 is 8 mm to 10 mm.

Specifically, as shown in FIG. 7 , in some embodiments of the presentapplication, the diameter H of the orthographic projection 143 of theresin 140 on the substrate 100 is 8 mm, and the height L of the resin140 in the direction perpendicular to the substrate 100 is 2 mm. Asshown in FIG. 8 , the line L1 connecting the center A of the lightemitter 130 and any point in the exit surface 141 forms a first angle αwith the first optical axis C, and the line L2 connecting the edge ofthe light emitter 130 and any point in the exit surface 141 forms asecond angle β with the first optical axis C.

The light having a first angle α that is greater than 0 degree and lessthan or equal to 40 degrees, among the light emitted from the center Aof the light emitter 130, is totally reflected by the concave surface142. In this way, the intensity of the light located above the firstoptical axis C can be reduced. After being reflected by the concavesurface 142, the light within this angle range enters the substrate 100,reflected by the substrate 100, and refracted and transmitted throughthe exit surface 141, which is conducive to improving the lightintensity at a position away from the first optical axis C, increasingthe spacing between adjacent light emitters 130, and reducing the numberof light emitters 130 to save energy. The light that coincides with thefirst optical axis C, that is, the light with an angle of 0 degree canbe directly transmitted through the concave surface of the exit surfaceto supplement the light intensity of the area above the center A of thelight emitter 130. The light with an angle greater than 40 degrees canbe directly refracted and transmitted through the exit surface 141,which is conducive to further improving the divergence angle anduniformity of the light. The light having a second angle β in a range of0 to 23 degrees, among the light emitted from the edge of the lightemitter 130, is transmitted through the concave surface 142, which isadvantageous to supplement the light intensity of the area above thecenter A of the light emitter 130, thereby improving the uniformity oflight and improving the display effect. At this time, when the lightmixing distance P is 5 mm, the width at half height of the standardizedwaveform is about 31 mm as shown in FIG. 6 b.

In some other embodiments of the present application, the diameter H ofthe orthographic projection 143 is 10 mm, and the height L of thelight-transmissive resin 140 in the direction perpendicular to thesubstrate 100 is 2.52 mm. At this time, the line L1 connecting thecenter A of the light emitter 130 and any point in the exit surface 141forms a first angle α with the first optical axis C, and the line L2connecting the edge of the light emitter 130 and any point in the exitsurface 141 forms a second angle β with the first optical axis C.

The light having the first angle α that is greater than 0 degree andless than or equal to 44 degrees, among the light emitted from thecenter A of the light emitter 130, is totally reflected by the concavesurface 142. In this way, the light intensity above the first opticalaxis C can be reduced. After being reflected by the concave surface 142,the light within this angle range enters the substrate 100, reflected bythe substrate 100, and refracted and transmitted through the exitsurface 141, which is conducive to improving the light intensity at aposition away from the first optical axis C, increasing the spacingbetween adjacent light emitters 130, and reducing the number of lightemitters 130 to save energy. The light that coincides with the firstoptical axis C, that is, the light with an angle of 0 degree can bedirectly transmitted through the concave surface of the exit surface tosupplement the light intensity of the area above the center A of thelight emitter 130. The light with an angle greater than 40 degrees canbe directly refracted and transmitted through the exit surface 141,which is conducive to further improving the divergence angle of thelight.

The light having a second angle β in a range of 0 to 10 degrees, amongthe light emitted from the edge of the light emitter 130, is transmittedthrough the concave surface 142, which is advantageous to supplement thelight intensity of the area above the center A of the light emitter 130,thereby improving the uniformity of light and improving the displayeffect. From the experimental verification, the light having a secondangle β in a range of 10 to 36 degrees is transmitted through theconcave surface 142 to the substrate, and the light whose second angle βis larger than 36 degrees is transmitted through the concave surface141. In this way, the scattering angle of light can be furtherincreased. At this time, when the light mixing distance P is 5 mm, thestandardized waveform is shown in FIG. 9 b , whose width at half heightis 34 mm.

As can be seen from the above embodiments, the concave surface 142 isprovided so that the exit surface 141 of the resin 140 can be dividedinto a first light transmitting portion, a total reflection portion, anda second light transmitting portion.

The first light transmitting portion refers to a region of the exitsurface 141 within a predetermined range centered on the first opticalaxis C. The first light transmitting portion may transmit first light,which is light emitted from the light emitter 130 with a small anglewith respect to the first optical axis C. For example, the first lightis emitted from the center A of the light emitter 130 with a first angleα of 0 degree; or, the first light is transmitted through the edge ofthe light emitter 130 with a second angle β in the range of 0 degree to10 degrees.

The total reflection portion is a region in the exit surface 141 that iscontinuously arranged around the first light transmitting portion so asto surround the first light transmitting portion. The total reflectionportion totally reflects at least the second light, which is the lightemitted from the light emitter 130 with a greater angle with respect tothe first optical axis C compared with the first light. For example, thesecond light is emitted from the center A of the light emitter 130 witha first angle α that is larger than 0 degree and less than or equal to44 degrees; or, the second light is emitted from the edge of the lightemitter 130 with a second angle β that is larger than 10 degrees andless than or equal to 36 degrees.

The second light transmitting portion is a region in the exit surface141 that is continuously arranged around the total reflection portion soas to surround the total reflection portion. The second lighttransmitting portion transmits the third light, which is the lightemitted from the light emitter 130 with a larger angle with respect tothe first optical axis C compared with the second light. For example,the third light can be emitted from the center A of the light emitter130 with a first angle α larger than 40 degrees. Alternatively, thethird light can be emitted from the edge of the light emitter 130 with asecond angle β larger than 36 degrees. Of course, the height of thelight-transmissive resin 140 in the direction perpendicular to thesubstrate 100 can be flexibly changed. For example, when the diameter ofthe orthographic projection 143 is 10 mm, the height of thelight-transmissive resin 140 in the direction perpendicular to thesubstrate 100 may also be 2.41 mm. At this time, the line L1 connectingthe center A of the light emitter 130 and any point in the exit surface141 forms a first angle α with the first optical axis C, and the line L2connecting the edge of the light emitter 130 and any point in the exitsurface 141 forms a second angle β with the first optical axis C.

The light having a first angle α that is greater than 0 degree and lessthan or equal to 15 degrees, among the light emitted from the center Aof the light emitter 130, is totally reflected by the concave surface142, the light in a range greater than 15 degrees is refracted andtransmitted through the exit surface 141; the light emitted from theedge of the light emitter 130 can be refracted and transmitted throughthe concave surface 142. At this time, when the light mixing distance Pis 5 mm, the width at half height of the standardized waveform is 27 mm,which is larger than 16.5 mm in the art. That is, it can also increasethe spacing between adjacent light emitters 130, thereby reducing thenumber of light emitters 130 and saving energy consumption whileensuring lightweight and thinness.

It is understandable that when the diameter of the orthographicprojection 143 is 10 mm and the height of the resin 140 in the directionperpendicular to the substrate 100 is 2.52 mm, compared with the aboveembodiment with the height of 2.41 mm, the spacing between adjacentlight emitters 130 can be further increased (the width at half height isincreased from 27 mm to 34 mm), which is conducive to further reducingthe number of light emitters 130 while ensuring lightweight and thethinness and saving energy consumption.

In some embodiments of the present application, phosphors are providedin the resin 140. When activated by the light from the light emitter130, the phosphors can emit light of other colors, which can also bemixed with the light from the light emitter 130 to obtain white light,so as to fulfill the need for white backlight.

In some other embodiments of the present application, light-transmissiveparticles may also be provided in the resin 140. For example, siliconeparticles, silica particles, melamine formaldehyde condensationparticles, or the like may be added, which is conducive to improving thelight transmittance of the resin 140 and further reducing the lightintensity loss.

As shown in FIG. 10 , the second aspect of the present applicationprovides a backlight module 1, which comprises the light emitting device10 according to the first aspect and a diffusion plate 120 arrangedabove the light emitting device 10.

The embodiments of the present application use the light emitting device10 according to the first aspect as a backlight source. Thelight-transmissive resin 140 is provided on the light emitter 130 in thelight emitting device 10, and a concave surface 142 is provided on theexit surface 141 of the light-transmissive resin 140, which isadvantageous to expand the divergence angle of light from each lightemitter 130, increase the spacing between adjacent light emitters 130,thereby reducing the number of light emitters 130 while ensuring thelightweight and the thinness and thereby saving energy consumption ofthe backlight module 1.

In some embodiments of the present application, the distance between thediffusion plate 120 and the substrate 100 is 3 mm to 10 mm. The distancebetween the diffusion plate 120 and the substrate 100 is the lightmixing distance P. When the distance is less than 3 mm, the displaypanel may have alternating light and dark portions and uneven color.When the distance is greater than 10 mm, it is unfavorable for thebacklight module 1 to be lighter in weight and thinner. Therefore, theembodiment of the present application is conducive to improving thelightweight and the thinness of the backlight module 1 while ensuringthe display effect of the display panel.

In some embodiments of the present application, the distance betweenadjacent light emitters is 20 mm or more, which is advantageous toreduce the number of light emitters 130 and save energy consumptionwhile ensuring the display effect of the display panel.

Specifically, embodiments and comparative examples are used to morespecifically explain the above embodiments. Table 1 shows the comparisonresults of the light mixing distance P and the distance between adjacentlight emitters in the conducted comparative example and the embodiments.In the comparative example, a layer of light-transmissive resin 111 ispotted on the LED 110 in the backlight module, and the diameter of thelight-transmissive resin 111 on the substrate 100 is 2.8 mm. In theembodiment of the present application, the light-transmissive resin 140is provided on the light emitter 130 (LED 110), the concave surface 142is also provided on the exit surface 141 of the light-transmissive resin140, the diameter H of the orthographic projection of thelight-transmissive resin 140 on the substrate 100 is 10 mm, and theheight L is 2.52 mm.

Table 1 shows the comparison results of the light mixing distance P andthe distance between adjacent LEDs in the comparative example and theembodiments.

light mixing width at spacing between distance half height adjacent LEDsP [mm] [mm] [mm] comparative 3 14.5 11 example embodiment 3 29.8 22comparative 5 16.5 12 example embodiment 5 34 25 comparative 10 24 18example embodiment 10 42 31

Table 1 shows the conditions that the light mixing distance P and thespacing between adjacent LEDs in the embodiment and the comparativeexample should meet when the display effect is guaranteed.

As can be seen from table 1, when the light mixing distances P are all 3mm, the spacing between adjacent LEDs in the comparative example is 11mm; and the spacing between adjacent LEDs in the embodiment of thepresent application can reach 22 mm. When the light mixing distances Pare all 10 mm, the spacing between adjacent LEDs in the comparativeexample is 18 mm; and the spacing between adjacent LEDs in theembodiment of the present application can reach 31 mm. Therefore, usingthe light emitting device 10 according to the first aspect as thebacklight in the embodiment of the present application is beneficial toreducing the number of light emitters 130 and reducing the energyconsumption of the backlight module 1 while ensuring the lightweight andthe thinness of the backlight module 1.

In a third aspect, the present application provides a display panelcomprising the backlight module according to the second aspect.

The display panel in the embodiment of the present application comprisesthe backlight module 1 according to the second aspect. The backlightmodule 1 comprises the light emitting device 10 according to the firstaspect. Wherein, the resin 140 is provided on the light emitter 130, anda concave surface 142 is provided on the exit surface 141 of the resin140, which is advantageous to expand the divergence angle of light fromeach light emitter 130, increase the spacing between adjacent lightemitters 130, thereby reducing the number of light emitters 130 whileensuring the lightweight and the thinness of the display panel andthereby saving energy consumption of the display panel.

It should be noted that the relationship terms herein such as “first”,“second”, and the like are only used for distinguishing one entity oroperation from another entity or operation, but do not necessarilyrequire or imply that there is any actual relationship or order betweenthese entities or operations. Moreover, the terms “include”, “comprise”or any other variants thereof are intended to cover non-exclusiveinclusions, so that processes, methods, articles or devices comprising aseries of elements comprise not only those elements listed but alsothose not specifically listed or the elements intrinsic to theseprocesses, methods, articles, or devices. Without further limitations,elements defined by the sentences “comprise(s) a” or “comprise(s) an” donot exclude that there are other identical elements in the processes,methods, articles, or devices which comprise these elements.

All the embodiments are described in corresponding ways, same or similarparts in each of the embodiments may be referred to one another, and theparts emphasized are differences from other embodiments. Especially forembodiments of a system, since they are similar to embodiments of amethod, the description thereof is relatively simple; the similar partscould refer to the parts in the description of embodiments of themethod.

The embodiments described above are merely preferred embodiments of thepresent application, and not intended to limit the scope of the presentapplication. Any modifications, equivalents, improvements or the likewithin the spirit and principle of the application should be comprisedin the scope of the application.

1. A light emitting device, comprising: a substrate; a plurality oflight emitters mounted on the substrate; and a light-transmissive resinon each light emitter of the light emitters, wherein the resin is inclose contact with the light emitter and a part of the substrate, and asurface of the resin away from the light emitter and the substrate formsan exit surface, wherein a center of the light emitter and a center ofthe exit surface are located in a first optical axis, and a region ofthe exit surface near the first optical axis is recessed toward thelight emitter to form a concave surface, which is configured to totallyreflect part of light emitted from the center of the light emitter andtransmit part of light emitted from an edge of the light emitter.
 2. Thelight emitting device according to claim 1, wherein, the first opticalaxis is perpendicular to the substrate, and a line connecting the centerof the light emitter and any point in the exit surface forms a firstangle with the first optical axis; light having the first angle that isgreater than 0 degree and less than or equal to 40 degrees, among thelight emitted from the center of the light emitter, is totally reflectedby the concave surface.
 3. The light emitting device according to claim1, wherein, the first optical axis is perpendicular to the substrate,and a line connecting the edge of the light emitter and any point in theexit surface forms a second angle with the first optical axis; lighthaving the second angle in a range of 0 to 10 degrees, among the lightemitted from the edge of the light emitter, is transmitted through theconcave surface.
 4. The light emitting device according to claim 1,wherein, an orthographic projection of the resin on the substrate iscircular; the orthographic projection has a diameter of 8 mm to 10 mm.5. The light emitting device according to claim 4, wherein, when thediameter of the orthographic projection is 8 mm, a height of the resinin a direction perpendicular to the substrate is 2 mm; when the diameterof the orthographic projection is 10 mm, the height of the resin in thedirection perpendicular to the substrate is 2.52 mm.
 6. The lightemitting device according to claim 1, wherein, phosphors orlight-transmissive particles are provided in the resin.
 7. A backlightmodule, comprising the light emitting device according to claim 1 and adiffusion plate arranged above the light emitting device.
 8. Thebacklight module according to claim 7, wherein, a distance between thediffusion plate and the substrate is 3 mm to 10 mm.
 9. The backlightmodule according to claim 7, wherein, a distance between adjacent lightemitters is 20 mm or more.
 10. A display panel, comprising the backlightmodule according to claim 7.